U.S. patent application number 15/522892 was filed with the patent office on 2017-11-09 for system and method for controlling the operation of a wind turbine.
The applicant listed for this patent is General Electric Company, Shuang GU, Veronica HERNANDEZ-ORTIZ, Xiongzhe HUANG, David Forest LOY, Ramy Michael SOURI, Danian ZHENG. Invention is credited to Shuang GU, Veronica HERNANDEZ-ORTIZ, Xiongzhe HUANG, David Forrest LOY, Ramy Michael SOURI, Danian ZHENG.
Application Number | 20170321654 15/522892 |
Document ID | / |
Family ID | 55856412 |
Filed Date | 2017-11-09 |
United States Patent
Application |
20170321654 |
Kind Code |
A1 |
ZHENG; Danian ; et
al. |
November 9, 2017 |
SYSTEM AND METHOD FOR CONTROLLING THE OPERATION OF A WIND
TURBINE
Abstract
A method for controlling the operation of a wind turbine may
generally include monitoring a current yaw position of a nacelle of
the wind turbine, wherein the current yaw position is located
within one of a plurality of yaw sectors defined for the nacelle.
In addition, the method may include monitoring a wind-dependent
parameter of the wind turbine and determining a variance of the
wind-dependent parameter over time, wherein the variance is
indicative of variations in a wind parameter associated with the
wind turbine. Moreover, the method may include determining at least
one curtailed operating setpoint for the wind turbine when the
variance exceeds a predetermined variance threshold, wherein the
curtailed operating setpoint(s) is determined based at least in
part on historical wind data for the yaw sector associated with the
current yaw position.
Inventors: |
ZHENG; Danian; (Greenville,
SC) ; GU; Shuang; (Shanghai, CN) ;
HERNANDEZ-ORTIZ; Veronica; (Greenville, SC) ; HUANG;
Xiongzhe; (Shanghai, CN) ; LOY; David Forrest;
(Schenectady, NY) ; SOURI; Ramy Michael;
(Greenville, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ZHENG; Danian
GU; Shuang
HERNANDEZ-ORTIZ; Veronica
HUANG; Xiongzhe
LOY; David Forest
SOURI; Ramy Michael
General Electric Company |
Greenville
Shanghai
Greenville
Shanghai
Schenectady
Greenville
Schenectady |
SC
SC
NY
SC
NY |
US
CN
US
CN
US
US
US |
|
|
Family ID: |
55856412 |
Appl. No.: |
15/522892 |
Filed: |
October 31, 2014 |
PCT Filed: |
October 31, 2014 |
PCT NO: |
PCT/CN2014/089970 |
371 Date: |
April 28, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F05B 2270/335 20130101;
Y02E 10/723 20130101; F03D 7/028 20130101; F03D 7/043 20130101;
G05B 15/02 20130101; F05B 2270/321 20130101; F05B 2270/322
20130101; F03D 7/0276 20130101; F05B 2270/1011 20130101; F03D 7/047
20130101; Y02E 10/72 20130101; F05B 2270/309 20130101; F05B
2270/329 20130101; F05B 2270/32 20130101 |
International
Class: |
F03D 7/04 20060101
F03D007/04; F03D 7/04 20060101 F03D007/04; G05B 15/02 20060101
G05B015/02 |
Claims
1. A method for controlling the operation of a wind turbine, the
method comprising: monitoring, with a computing device, a current
yaw position of a nacelle of the wind turbine, the current yaw
position being located within one of a plurality of yaw sectors
defined around a range of travel for the nacelle; monitoring, with
the computing device, a wind-dependent parameter of the wind
turbine; determining, with the computing device, a variance of the
wind-dependent parameter over time, wherein the variance is
indicative of variations in a wind parameter associated with the
wind turbine; and determining, with the computing device, at least
one curtailed operating setpoint for the wind turbine when the
variance exceeds a predetermined variance threshold, wherein the at
least one curtailed operating setpoint is determined based at least
in part on historical wind data for the yaw sector associated with
the current yaw position.
2. The method of claim 1, wherein determining the at least one
curtailed operating setpoint comprises selecting an operating
setpoint for the at least one curtailed operating setpoint that is
at or below a setpoint limit established for the at least one
curtailed operating setpoint based on the historical wind data for
the yaw sector associated with the current yaw position.
3. The method of claim 2, wherein the setpoint limit is varied
based on whether the historical wind data indicates a pattern of
recurring variations in the wind parameter.
4. The method of claim 1, further comprising monitoring the wind
parameter associated with the wind turbine.
5. The method of claim 4, wherein the wind parameter comprises at
least one of wind speed, wind direction, wind gust or turbulence
intensity.
6. The method of claim 4, wherein the determining the at least one
curtailed operating setpoint comprises determining the at least one
curtailed operating setpoint when the variance exceeds the
predetermined variance threshold and when the wind parameter
exceeds a predetermined wind parameter threshold.
7. The method of claim 1, wherein the wind-dependent parameter
comprises at least one of generator speed, generator torque or
power output of the wind turbine.
8. The method of claim 1, wherein determining the variance of the
wind-dependent parameter over time comprises determining a standard
deviation of the wind-dependent parameter over time.
9. The method of claim 1, wherein the at least one constrained
operating setpoint comprises at least one of a generator speed
setpoint or a generator torque setpoint.
10. The method of claim 1, further comprising selecting at least
one non-curtailed operating setpoint for the wind turbine when the
variance does not exceed the predetermined variance threshold.
11. The method of claim 10, wherein the at least one constrained
operating setpoint corresponds to a reduction in at least one of a
generator speed setpoint or a generator torque setpoint as compared
to the at least one non-curtailed operating setpoint such that the
wind turbine is de-rated when the operation of the wind turbine is
transitioned from the at least one non-curtailed operating setpoint
to the at least one constrained operating setpoint.
12. The method of claim 1, further comprising controlling the
operation of the wind turbine based on the at least one curtailed
operating setpoint.
13. A method for controlling the operation of a wind turbine, the
method comprising: monitoring, with a computing device, a current
yaw position of a nacelle of the wind turbine, the current yaw
position being located within one of a plurality of yaw sectors
defined around a range of travel for the nacelle; monitoring, with
the computing device, a generator speed of the wind turbine;
monitoring, with the computing device, a wind speed associated with
the wind turbine; determining, with the computing device, a
standard deviation of the generator speed over time, wherein the
variance is indicative of variations in the wind speed;
determining, with the computing device, at least one curtailed
operating setpoint for the wind turbine when the variance exceeds a
predetermined variance threshold and when the wind speed exceeds a
predetermined wind speed threshold, wherein the at least one
curtailed operating setpoint is determined based at least in part
on historical wind data for the yaw sector associated with the
current yaw position; and operating the wind turbine based on the
at least one curtailed operating setpoint.
14. The method of claim 13, wherein determining the at least one
curtailed operating setpoint comprises selecting an operating
setpoint for the at least one curtailed operating setpoint that is
at or below a setpoint limit established for the at least one
curtailed operating setpoint based on the historical wind data for
the yaw sector associated with the current yaw position.
15. The method of claim 14, wherein the setpoint limit is varied
based on whether the historical wind data indicates a pattern of
recurring variations in the wind parameter.
16. A system for controlling the operation of a wind turbine, the
system comprising: a computing device including a processor and
associated memory, the memory storing instructions that, when
implemented by the processor, configure the computing device to:
monitor a current yaw position of a nacelle of the wind turbine,
the current yaw position being located within one of a plurality of
yaw sectors defined around a range of travel for the nacelle;
monitor a wind-dependent parameter of the wind turbine; determine a
variance of the wind-dependent parameter over time, wherein the
variance is indicative of variations in a wind parameter associated
with the wind turbine; and determine at least one curtailed
operating setpoint for the wind turbine when the variance exceeds a
predetermined variance threshold, wherein the at least one
curtailed operating setpoint is determined based at least in part
on historical wind data for the yaw sector associated with the
current yaw position.
17. The system of claim 16, wherein the computing device is
configured to establish a setpoint limit for the at least one
curtailed operating setpoint based on the historical wind data for
the yaw sector associated with the current yaw position such that
the at least one curtailed operating setpoint is selected as an
operating setpoint that is at or below the established setpoint
limit.
18. The system of claim 17, wherein the setpoint limit is varied
based on whether the historical wind data indicates a pattern of
recurring variations in the wind parameter.
19. The system of claim 16, wherein the computing device is further
configured to monitor the wind parameter associated with the wind
turbine, the wind parameter correspond to at least one of wind
speed, wind direction, wind gust or turbulence intensity.
20. The system of claim 16, wherein the wind-dependent parameter
comprises at least one of generator speed, generator torque or
power output of the wind turbine.
Description
FIELD OF THE INVENTION
[0001] The present subject matter relates generally to wind
turbines and, more particularly, to a system and method for
controlling the operation of wind turbine in a manner that avoids
overspeed and/or runaway conditions due to rapidly changing wind
conditions.
BACKGROUND OF THE INVENTION
[0002] Wind power is considered one of the cleanest, most
environmentally friendly energy sources presently available and
wind turbines have gained increased attention in this regard. A
modern wind turbine typically includes a tower, generator, gearbox,
nacelle, and one or more rotor blades. The rotor blades are the
primary elements for converting wind energy into electrical energy.
The blades typically have the cross-sectional profile of an airfoil
such that, during operation, air flows over the blade producing a
pressure difference between its sides. Consequently, a lift force,
which is directed from the pressure side towards the suction side,
acts on the blade. The lift force generates torque on the main
rotor shaft, which is geared to a generator for producing
electricity.
[0003] In many instances, wind turbines are operated at locations
with significantly varying wind conditions. For example, wind
turbines are often subject to sudden wind gusts, high turbulence
intensities and/or abrupt changes in the direction of the wind.
Such rapidly changing wind conditions make it difficult to control
the operation of a wind turbine in a manner that avoids tripping of
the turbine due to overspeed and/or runaway conditions. For
instance, when there is an abrupt change in the wind direction at a
wind turbine site, a wind turbine located at the site perceives the
change in wind direction as a drop in wind speed. As a result, the
typical control action implemented by the turbine controller is to
pitch the blades in a manner that provides increased efficiency at
the perceived, lower wind speeds. Unfortunately, for a wind turbine
site with rapidly changing wind conditions, the wind direction may
shift back to the original direction in a very short period of
time, thereby immediately subjecting the wind turbine to increased
wind speeds. Such an abrupt increase in the wind speed following a
control action to pitch the rotor blades to a more efficient pitch
angle can lead to overspeed and runaway conditions for the wind
turbine, which may necessitate tripping the turbine to avoid
component damage and/or unsafe operation.
[0004] Accordingly, an improved system and method that allows for
the operation of a wind turbine to be effectively and efficiently
controlled despite substantially varying wind conditions would be
welcomed in the technology.
BRIEF DESCRIPTION OF THE INVENTION
[0005] Aspects and advantages of the invention will be set forth in
part in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
[0006] In one aspect, the present subject matter is directed to a
method for controlling the operation of a wind turbine. The method
may generally include monitoring a current yaw position of a
nacelle of the wind turbine, wherein the current yaw position is
located within one of a plurality of yaw sectors defined for the
nacelle. In addition, the method may include monitoring a
wind-dependent parameter of the wind turbine and determining a
variance of the wind-dependent parameter over time, wherein the
variance is indicative of variations in a wind parameter associated
with the wind turbine. Moreover, the method may include determining
at least one curtailed operating setpoint for the wind turbine when
the variance exceeds a predetermined variance threshold, wherein
the curtailed operating setpoint(s) is determined based at least in
part on historical wind data for the yaw sector associated with the
current yaw position.
[0007] In another aspect, the present subject matter is directed to
a method for controlling the operation of a wind turbine. The
method may generally include monitoring a current yaw position of a
nacelle of the wind turbine, wherein the current yaw position is
located within one of a plurality of yaw sectors defined for the
nacelle. The method may also include monitoring a generator speed
of the wind turbine, monitoring a wind speed associated with the
wind turbine, and determining a standard deviation of the generator
speed over time, wherein the variance is indicative of variations
in the wind speed. In addition, the method may include determining
at least one curtailed operating setpoint for the wind turbine when
the variance exceeds a predetermined variance threshold and when
the wind speed exceeds a predetermined wind speed threshold,
wherein the curtailed operating setpoint(s) is determined based at
least in part on historical wind data for the yaw sector associated
with the current yaw position. Moreover, the method may include
operating the wind turbine based on the curtailed operating
setpoint(s).
[0008] In a further aspect, the present subject matter is directed
to a system for controlling the operation of a wind turbine. The
system may generally include a computing device including a
processor and associated memory. The memory may store instructions
that, when implemented by the processor, configure the computing
device to monitor a current yaw position of a nacelle of the wind
turbine, wherein the current yaw position is located within one of
a plurality of yaw sectors defined for the nacelle. The computing
device may also be configured to monitor a wind-dependent parameter
of the wind turbine and determine a variance of the wind-dependent
parameter over time, wherein the variance is indicative of
variations in a wind parameter associated with the wind turbine. In
addition, the computing device may be configured to determine at
least one curtailed operating setpoint for the wind turbine when
the variance exceeds a predetermined variance threshold, wherein
the curtailed operating setpoint(s) is determined based at least in
part on historical wind data for the yaw sector associated with the
current yaw position.
[0009] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] A full and enabling disclosure of the present invention,
including the best mode thereof, directed to one of ordinary skill
in the art, is set forth in the specification, which makes
reference to the appended figures, in which:
[0011] FIG. 1 illustrates a perspective view of one embodiment of a
wind turbine.
[0012] FIG. 2 illustrates an internal view of one embodiment of a
nacelle of the wind turbine shown in FIG. 1
[0013] FIG. 3 illustrates a schematic diagram of one embodiment of
a turbine controller suitable for use within a wind turbine in
accordance with aspects of the present subject matter;
[0014] FIG. 4 illustrates a flow diagram of one embodiment of a
control algorithm that may be implemented by a turbine controller
in order to control the operation of a wind turbine in accordance
with aspects of the present subject matter;
[0015] FIG. 5 illustrates an example of how the yaw travel range
for a nacelle may be divided into a plurality of individual yaw
sectors; and
[0016] FIG. 6 illustrates a flow diagram of one embodiment of a
method for controlling the operation of a wind turbine in
accordance with aspects of the present subject matter, particularly
illustrating method elements for implementing an embodiment of the
control algorithm shown in FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope or spirit of the invention. For instance, features
illustrated or described as part of one embodiment can be used with
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0018] In general, the present subject matter is directed to a
system and method for controlling the operation of a wind turbine.
In several embodiments, the disclosed system and method may be
utilized to curtail or de-rate the operation of a wind turbine when
the turbine is being subjected to rapidly changing wind conditions.
Specifically, in one embodiment, the turbine controller of a wind
turbine may be configured to monitor the variability of one or more
wind-dependent parameters of the wind turbine, which, in turn, may
provide an indication of variations in one or more wind parameters
associated with the wind turbine. For example, the turbine
controller may be configured to calculate the standard deviation in
the generator speed occurring over a relatively short period of
time (e.g., over 5 seconds). A relatively high standard deviation
for the generator speed (e.g., higher than a predetermined variance
threshold defined for the generator speed) may indicate that the
wind turbine is currently experiencing rapidly changing wind
conditions, such as abrupt changes in the wind speed and/or wind
direction, sudden wind gusts and/or increased turbulence intensity.
In such instance, the turbine controller may be configured to
de-rate the wind turbine by selecting one or more curtailed
operating setpoints for the wind turbine, such as a reduced
generator speed setpoint or a reduced generator torque setpoint.
Once the variability in the generator speed is reduced, the turbine
controller may then be configured to up-rate the wind turbine back
to its normal or non-curtailed operating setpoints.
[0019] Additionally, in several embodiments, when de-rating the
wind turbine due to high variability in the monitored
wind-dependent parameter, the turbine controller may be configured
to take into account historical wind data associated with the yaw
sector within which the nacelle is currently located to select an
appropriate curtailed operating setpoint(s) for the turbine.
Specifically, the yaw range of travel of the nacelle (e.g., a 360
degree circle) may be divided into a plurality of different yaw
sectors. In such embodiments, the turbine controller may be
provided with or may be configured to collect wind data associated
with each wind sector. For example, wind data related to the
variability in the wind speed, wind direction, wind gusts and/or
turbulence intensity experienced by each yaw sector may be stored
within the controller's memory. The turbine controller may then
reference the historical wind data when selecting the curtailed
operating setpoint(s) for the wind turbine. In particular, if the
yaw sector within which the nacelle is currently located typically
experiences rapidly changing wind conditions, the controller may
set a setpoint limit(s) for the operating setpoint(s) that provides
a relatively high operating margin in order to avoid overspeed
and/or runaway conditions. However, if the historical wind data
indicates that the yaw sector is typically not subjected to rapidly
changing wind conditions, the controller may set a setpoint
limit(s) for the operating setpoint(s) that provides a lower
operating margin.
[0020] Referring now to the drawings, FIG. 1 illustrates a
perspective view of one embodiment of a wind turbine 10 in
accordance with aspects of the present subject matter. As shown,
the wind turbine 10 generally includes a tower 12 extending from a
support surface 14, a nacelle 16 mounted on the tower 12, and a
rotor 18 coupled to the nacelle 16. The rotor 18 includes a
rotatable hub 20 and at least one rotor blade 22 coupled to and
extending outwardly from the hub 20. For example, in the
illustrated embodiment, the rotor 18 includes three rotor blades
22. However, in an alternative embodiment, the rotor 18 may include
more or less than three rotor blades 22. Each rotor blade 22 may be
spaced about the hub 20 to facilitate rotating the rotor 18 to
enable kinetic energy to be transferred from the wind into usable
mechanical energy, and subsequently, electrical energy. For
instance, the hub 20 may be rotatably coupled to an electric
generator 24 (FIG. 2) positioned within the nacelle 16 to permit
electrical energy to be produced.
[0021] The wind turbine 10 may also include a turbine control
system or turbine controller 26 centralized within the nacelle 16
(or disposed at any other suitable location within and/or relative
to the wind turbine 10). In general, the turbine controller 26 may
comprise a computing device or any other suitable processing unit.
Thus, in several embodiments, the turbine controller 26 may include
suitable computer-readable instructions that, when implemented,
configure the controller 26 to perform various different functions,
such as receiving, transmitting and/or executing wind turbine
control signals. As such, the turbine controller 26 may generally
be configured to control the various operating modes (e.g.,
start-up or shut-down sequences) and/or components of the wind
turbine 10. For example, the controller 26 may be configured to
adjust the blade pitch or pitch angle of each rotor blade 22 (i.e.,
an angle that determines a perspective of the blade 22 with respect
to the direction of the wind) about its pitch axis 28 in order to
control the rotational speed of the rotor blade 22 and/or the power
output generated by the wind turbine 10. For instance, the turbine
controller 26 may control the pitch angle of the rotor blades 22,
either individually or simultaneously, by transmitting suitable
control signals to one or more pitch drives or pitch adjustment
mechanisms 32 (FIG. 2) of the wind turbine 10. Similarly, the
turbine controller 26 may be configured to adjust the yaw angle of
the nacelle 16 (i.e., an angle that determines a perspective of the
nacelle 16 relative to the direction of the wind) about a yaw axis
44 of the wind turbine 10. For example, the controller 26 may
transmit suitable control signals to one or more yaw drive
mechanisms 46 (FIG. 2) of the wind turbine 10 to automatically
control the yaw angle.
[0022] Referring now to FIG. 2, a simplified, internal view of one
embodiment of the nacelle 16 of the wind turbine 10 shown in FIG. 1
is illustrated. As shown, a generator 24 may be disposed within the
nacelle 16. In general, the generator 24 may be coupled to the
rotor 18 for producing electrical power from the rotational energy
generated by the rotor 18. For example, as shown in the illustrated
embodiment, the rotor 18 may include a rotor shaft 38 coupled to
the hub 20 for rotation therewith. The rotor shaft 38 may, in turn,
be rotatably coupled to a generator shaft 40 of the generator 24
through a gearbox 42. As is generally understood, the rotor shaft
38 may provide a low speed, high torque input to the gearbox 42 in
response to rotation of the rotor blades 22 and the hub 20. The
gearbox 42 may then be configured to convert the low speed, high
torque input to a high speed, low torque output to drive the
generator shaft 40 and, thus, the generator 24.
[0023] Additionally, as indicated above, the controller 26 may also
be located within the nacelle 16 (e.g., within a control box or
panel). However, in other embodiments, the controller 26 may be
located within any other component of the wind turbine 10 or at a
location outside the wind turbine 10. As is generally understood,
the controller 26 may be communicatively coupled to any number of
the components of the wind turbine 10 in order to control the
operation of such components. For example, as indicated above, the
controller 26 may be communicatively coupled to each pitch
adjustment mechanism 32 of the wind turbine 10 (one for each rotor
blade 22) via a pitch controller 30 to facilitate rotation of each
rotor blade 22 about its pitch axis 28. Similarly, the controller
26 may be communicatively coupled to one or more yaw drive
mechanisms 46 of the wind turbine 10 for adjusting the yaw angle or
position of the nacelle 16. For instance, the yaw drive
mechanism(s) 46 may be configured to adjust the yaw position by
rotationally engaging a suitable yaw bearing 48 (also referred to
as a slewring or tower ring gear) of the wind turbine 10, thereby
allowing the nacelle 16 to be rotated about its yaw axis 44.
[0024] In addition, the wind turbine 10 may also include one or
more sensors for monitoring various operating parameters of the
wind turbine 10. For example, in several embodiments, the wind
turbine 10 may include one or more shaft sensors 60 configured to
monitor one or more shaft-related operating parameters of the wind
turbine 10, such as the loads acting on the rotor shaft 38 (e.g.,
thrust, bending and/or torque loads), the deflection of the rotor
shaft 38 (e.g., including shaft bending), the rotational speed of
the rotor shaft 38 and/or the like. The wind turbine may also
include one or more blades sensors 62 (FIGS. 1 and 2) configured to
monitor one or more blade-related operating parameters of the wind
turbine 10, such as the loads acting on the blades 22 (e.g.,
bending loads), the deflection of the blades 22 (e.g., including
blade bending, twisting and/or the like), the vibration of the
blades 22, the noise generated by the blades 22, the pitch angle of
the blades 22, the rotational speed of the blades 22 and/or the
like. Additionally, the wind turbine 10 may include one or more
generator sensors 64 configured to monitor one or more
generator-related operating parameters of the wind turbine 10, such
as the power output of the generator 24, the rotational speed of
the generator 24, the generator torque and/or the like.
[0025] Moreover, the wind turbine 10 may also include various other
sensors for monitoring numerous other turbine operating parameters.
For example, as shown in FIG. 2, the wind turbine 10 may include
one or more tower sensors 66 for monitoring various tower-related
operating parameters, such as the loads acting the tower 12, the
deflection of the tower 12 (e.g., tower bending and/or twisting),
tower vibrations and/or the like. In addition, the wind turbine 10
may include one or more wind sensors 68 for monitoring one or more
wind parameters associated with the wind turbine 10, such as the
wind speed, the wind direction, wind gusts, the turbulence or
turbulence intensity of the wind and/or the like. Similarly, the
wind turbine 10 may include one or more hub sensors 70 for
monitoring various hub-related operating conditions (e.g., the
loads transmitted through the hub 20, hub vibrations and/or the
like), one or more nacelle sensors 72 for monitoring one or more
nacelle-related operating conditions (e.g., the loads transmitted
through the nacelle 16, nacelle vibrations, the yaw angle or
position of the nacelle 16 and/or the like) and/or one or more
gearbox sensors 74 for monitoring one or more gearbox-related
operating conditions (e.g., gearbox torque, gearbox loading,
rotational speeds within the gearbox and/or the like). Of course,
the wind turbine 10 may further include various other suitable
sensors for monitoring any other suitable operating conditions of
the wind turbine 10. It should be appreciated that the various
sensors described herein may correspond to pre-existing sensors of
a wind turbine 10 and/or sensors that have been specifically
installed within the wind turbine 10 to allow one or more operating
parameters to be monitored.
[0026] It should also be appreciated that, as used herein, the term
"monitor" and variations thereof indicates that the various sensors
of the wind turbine 10 may be configured to provide a direct
measurement of the operating parameters being monitored or an
indirect measurement of such operating parameters. Thus, the
sensors may, for example, be used to generate signals relating to
the operating parameter being monitored, which can then be utilized
by the controller 26 to determine the actual operating parameters.
For instance, measurement signals provided by generator sensor(s)
64 that measure the power output of the generator 24 along with the
measurement signals provided by the blade sensor(s) 62 that measure
the pitch angle of the rotor blades 22 may be used by the
controller 26 to estimate one or more wind-related parameters
associated with the wind turbine 10, such as the wind speed.
[0027] Referring now to FIG. 3, a block diagram of one embodiment
of suitable components that may be included within the controller
26 is illustrated in accordance with aspects of the present subject
matter. As shown, the controller 26 may include one or more
processor(s) 76 and associated memory device(s) 78 configured to
perform a variety of computer-implemented functions (e.g.,
performing the methods, algorithms, calculations and the like
disclosed herein). As used herein, the term "processor" refers not
only to integrated circuits referred to in the art as being
included in a computer, but also refers to a controller, a
microcontroller, a microcomputer, a programmable logic controller
(PLC), an application specific integrated circuit, and other
programmable circuits. Additionally, the memory device(s) 78 may
generally comprise memory element(s) including, but are not limited
to, computer readable medium (e.g., random access memory (RAM)),
computer readable non-volatile medium (e.g., a flash memory), a
floppy disk, a compact disc-read only memory (CD-ROM), a
magneto-optical disk (MOD), a digital versatile disc (DVD) and/or
other suitable memory elements. Such memory device(s) 78 may
generally be configured to store suitable computer-readable
instructions that, when implemented by the processor(s) 76,
configure the controller 26 to perform various functions including,
but not limited to, implementing the control algorithm(s) 100
and/or method(s) 200 disclosed herein with reference to FIGS. 4 and
6.
[0028] Additionally, the controller 26 may also include a
communications module 80 to facilitate communications between the
controller(s) 26 and the various components of the wind turbine 10.
For instance, the communications module 80 may include a sensor
interface 82 (e.g., one or more analog-to-digital converters) to
permit the signals transmitted by the sensor(s) 60, 62, 64, 66, 68,
70, 72, 74 to be converted into signals that can be understood and
processed by the processors 76.
[0029] Referring now to FIG. 4, a diagram of one embodiment of a
control algorithm 100 that may be implemented by a turbine
controller 26 in order to control the operation of a wind turbine
10 is illustrated in accordance with aspects of the present subject
matter. As indicated above, the disclosed algorithm 100 may, in
several embodiments, be advantageously applied when a wind turbine
10 is subject to one or more substantially varying wind parameters,
such as a wind speed, wind direction, wind gust and/or turbulence
intensity that varies significantly over time. In particular, the
algorithm 100 described herein may allow for the operation of a
wind turbine 10 to be de-rated or curtailed in an efficient and
effective manner in instances in which the local wind parameter(s)
for the turbine 10 are changing significantly within a relatively
short period of time. Such de-rating or curtailment of the wind
turbine 10 may allow for overspeed and/or runaway conditions to be
avoided despite the occurrence of sudden or rapid changes in the
wind parameter(s) associated with the wind turbine 10.
[0030] As shown in FIG. 4, the turbine controller 26 may be
configured to receive one or more input signals associated with one
or more monitored operating parameters of the wind turbine 10, such
as one or more wind parameters 102 and one or more wind-dependent
parameters 104. For example, the disclosed algorithm 100 will
generally be described herein with reference to the turbine
controller 26 receiving input signals associated with a monitored
wind speed for the wind turbine 10. However, in other embodiments,
the turbine controller 26 may be configured to monitor any other
suitable wind parameters 102 associated with the wind turbine 10,
such as the wind direction, the turbulence intensity of the wind,
wind gusts and/or the like. Additionally, the disclosed algorithm
100 will generally be described herein with reference to the
turbine controller 26 receiving input signals associated a
monitored generator speed. However, in other embodiments, the
turbine controller 26 may be configured to monitor any other
suitable wind-dependent parameter(s) 104 that provides an
indication of the variability in one or more of the wind
parameter(s), such as the power output of the wind turbine 10, the
generator torque and/or the like.
[0031] In several embodiments, the controller 26 may be configured
to apply one or more suitable filters or S-functions (as shown at
box 106) to the monitored wind parameter(s) 102. For example, as
indicated above, the turbine controller 26 may be configured to
estimate the wind speed based on one or more other monitored
operating parameters of the wind turbine 10, such as by estimating
the wind speed based on the pitch angle of the rotor blades 22 and
the power output of the generator 24. In such embodiments, the
estimated wind speed provided by the turbine controller 26 may be
highly variable. Thus, in several embodiments, application of the
corresponding filter(s) and/or S-function(s) may allow for the
variations in the estimated wind speed to be accommodated within
the system.
[0032] For example, in one embodiment, the controller 26 may be
configured to input the monitored wind parameter(s) 102 into a
low-pass filter. As is generally understood, the low-pass filter
may be configured to filter out the high frequency signals
associated with the monitored wind parameter(s) 102, thereby
providing more reliable data. For instance, the low-pass filter may
be configured to pass low-frequency signals associated with the
monitored wind parameter(s) 102 but attenuate (i.e. reduces the
amplitude of) signals with frequencies higher than a given cutoff
frequency.
[0033] Additionally, in one embodiment, the filtered or unfiltered
wind parameter(s) 102 may be input into an S-function to smooth or
stabilize the input signals associated with the wind parameter(s)
102. As is generally understood, the S-function may correspond to a
mathematical equation having an S-shape. For example, in one
embodiment, the S-function may be represented by:
y=k/(1+a*exp(b*x)), wherein k, a, and b are parameters of the
S-curve, x is the input, and y is the output. Of course, it should
be understood by those skilled in the art that the S-function may
also be any other suitable mathematical function, e.g. a Sigmoid
function.
[0034] Referring still to FIG. 4, the turbine controller 26 may
also be configured to calculate a variance in the wind-dependent
parameter(s) 104 over time (indicated at box 108), with the
variance generally being indicative of the variability in the
monitored wind parameter(s). Specifically, fluctuations in one or
more of the wind parameter(s) 102 associated with the wind turbine
10 may result in corresponding variations in one or more of the
wind-dependent parameters 104. Thus, by calculating the variance in
the monitored wind-dependent parameter(s) 104 over time, such
variance may provide a strong indication of the instability or
variability in the associated wind parameter(s) 102.
[0035] In several embodiments, the variance calculated by the
turbine controller 26 may correspond to a standard deviation of the
wind-dependent parameter(s) 104 occurring across a given time
period. For example, the generator speed may be continuously
monitored and stored within the controller's memory 78. The stored
data may then be utilized to calculate the standard deviation of
the generator speed across a relatively short period of time (e.g.,
5 seconds). A high standard deviation may indicate that one or more
of the wind parameter(s) 102 is rapidly changing whereas a low
standard deviation may indicate that the wind parameter(s) 102 is
remaining relatively stable over the specific time period.
[0036] Additionally, the turbine controller 26 may, in several
embodiments, be configured to apply one or more adaptive filters
(not shown) to smooth and/or stabilize the calculated variance 108
so as to improve the overall system stability. In such embodiments,
the adaptive filter(s) may correspond to any suitable type of
filter(s), such as a low-pass filter, high-pass filter and/or
band-pass filter.
[0037] As shown in FIG. 4, based on the calculated variance and the
wind parameter(s) input, the controller 26 may be configured to
select or calculate one or more operating setpoints for the wind
turbine 10, such as a generator speed setpoint and/or a generator
torque setpoint. In doing so, the turbine controller 26 may be
configured (at box 110) to compare the monitored wind parameter(s)
to a predetermined wind parameter threshold and the calculated
variance to a predetermined variance threshold in order to
determine whether to apply the normal or non-curtailed operating
setpoints typically provided for the wind turbine (indicated at box
112) or to instead apply one or more curtailed operating setpoints
so as to de-rate the wind turbine 10 (indicated at box 114).
Specifically, in several embodiments, the threshold values for the
wind parameter and variance thresholds may be selected such that,
when each input parameter exceeds its corresponding threshold, it
is indicative of operating conditions in which there is a high
likelihood that the wind turbine 10 may experience an overspeed or
runway condition. In such instance, the turbine controller 26 may
be configured to select a reduced operating setpoint(s) that
curtails or de-rates the operation of the wind turbine 10, thereby
allowing the turbine 10 to ride-through the unstable operating
conditions with greater safety or operating margins.
[0038] For example, in a particular embodiment, a predetermined
variance threshold may be utilized that corresponds to a standard
deviation value for the generator speed above which it can be
inferred that the wind turbine 10 is being subjected to dynamic,
rapidly changing wind conditions. Similarly, in such an embodiment,
the predetermined wind parameter threshold may, for example,
correspond to a wind speed value above which there is an increased
likelihood for the wind turbine 10 to be placed in a potential
overspeed or runway condition given the dynamic, rapidly changing
wind conditions. As such, when the standard deviation for the
generator speed exceeds the corresponding variance threshold and
the wind speed exceeds the corresponding wind speed threshold, the
turbine 10 may be de-rated by applying a reduced or curtailed
operating setpoint(s) in a manner so as to prevent the
overspeed/runway condition. For instance, the generator speed
setpoint may be reduced in a manner that provides for an increased
speed margin for the wind turbine 10, thereby allowing the turbine
10 to continue to be safely operated despite the dynamic and
varying wind conditions.
[0039] It should be appreciated that, in several embodiments, the
threshold values associated with the variance and the wind
parameter correspond to minimum threshold values. Additionally, in
several embodiments, a maximum threshold value may also be
associated with the variance and/or wind parameter for determining
when to apply the curtailed operating setpoint(s). For example, in
a particular embodiment, it may be desired that the monitored wind
parameter (e.g., wind speed) fall within a given range of values
(e.g., a range bound by a predetermined minimum threshold and a
predetermined maximum threshold) prior to applying the curtailed
operating setpoint(s).
[0040] Additionally, as shown in FIG. 4, the turbine controller 26
may be configured to analyze yaw sector data associated with the
wind turbine 10 (indicated at box 116) when selecting a curtailed
operating setpoint(s) for the turbine 10. Specifically, in several
embodiments, the yaw travel range for the nacelle 16 may be divided
into a plurality of yaw sectors, with each yaw sector corresponding
to an angular section of the entire travel range. For example, FIG.
5 illustrates a plurality of yaw sectors 140 defined for a nacelle
16 having a 360 degree yaw travel range (indicated by circle 142).
As shown in FIG. 5, the yaw travel range 142 has been divided into
sixteen different yaw sectors 140, with each yaw sector 140
corresponding to a 22.5 degree angular section of the travel range
142. However, in other embodiments, the yaw travel range 142 may be
divided into any other suitable number of yaw sectors 140
correspond to any suitable angular section of the overall travel
range. For example, in one embodiment, each yaw sector 140 may
correspond to an angular section of the yaw travel range ranging
from about 10 degrees to about 30 degrees, such as from about 15
degrees to about 25 degrees and all other subranges
therebetween.
[0041] For each yaw sector 140 defined for the wind turbine 10, the
turbine controller 26 may be configured to store historical wind
data corresponding to one or more monitored wind parameter(s) for
the yaw sector. For example, historical wind speed measurements,
wind gust measurements, wind direction measurements, turbulence
intensity measurements and/or the like may be collected and stored
within the controller's memory 78 for each yaw sector 140. As a
result, it may be determined whether a given yaw sector 140 is
typically subjected to varying wind conditions based on its
historical wind data. For example, the historical wind data may
indicate that a particular yaw sector 140 is subject to recurring
wind gusts or systematically experiences sudden shifts in wind
direction.
[0042] In several embodiments, the historical wind data may be
utilized to define one or more setpoint limits for the curtailed
operating setpoint(s). Specifically, as indicated above, the
controller 26 may be communicatively coupled to one or more sensors
(e.g., a nacelle sensor(s) 72) that allow for the yaw angle or
position of the nacelle 16 to be monitored, which may then allow
the controller 26 to identify the yaw sector 140 within which the
nacelle 16 is currently located (e.g., the current location of the
nacelle 16 is indicated by arrow 144 in FIG. 5 such that the
nacelle 16 is currently located within the cross-hatched yaw sector
140). The turbine controller 26 may then reference the historical
data stored for the relevant yaw sector 140 to determine of such
yaw sector 140 typically experiences substantially varying wind
conditions. If the data indicates that the yaw sector 140 is
typically not subjected to rapidly changing wind conditions, the
turbine controller 26 may infer that the high variance calculated
for the wind-dependent parameter(s) 104 may be due to another
factor(s) or may simply correspond to an atypical operating event.
In such instance, the setpoint limit(s) selected for the curtailed
operating setpoint(s) may correspond to a relatively high operating
setpoint(s) given that the variance is probably not due to
recurring variations in the wind conditions. For example, the
setpoint limit for the generator speed setpoint may be defined as a
speed value that is only slightly less than the generator speed
setpoint that would otherwise be commanded if the turbine
controller 26 was utilizing its normal or non-curtailed operating
setpoints. Alternatively, if the data indicates that the yaw sector
140 has historically been subjected to rapidly changing wind
conditions, the turbine controller 26 may infer that the high
variance calculated for the wind-dependent parameter(s) 104 is due
to the varying wind conditions. In such instance, the setpoint
limit(s) selected for the curtailed operating setpoint(s) may be
correspond to a lower operating setpoint(s). For example, the
setpoint limit for the generator speed setpoint may be defined as a
speed value that is significantly less than the generator speed
setpoint that would otherwise be used if the turbine controller 26
was commanding its normal or non-curtailed operating setpoints,
thereby allowing for a larger speed margin to be provided for the
wind turbine 10 given the increased likelihood of substantially
varying wind conditions.
[0043] Referring back to FIG. 4, in several embodiments, the
turbine controller 26 may also be configured to apply one or more
suitable filters or S-functions (indicated at box 118) to the
operating setpoint(s) determined by the controller 26 in order to
smooth and stabilize the operation of the wind turbine 10 when
transitioning between normal and curtailed operation. For example,
in one embodiment, a low-pass filter may be utilized to limit the
rate at which the wind turbine 10 is de-rated when transitioning
from the use of non-curtailed operating setpoints to the use of
curtailed operating setpoints. Similarly, the low pass filter may
also be utilized to limit the rate at which the wind turbine 10 is
up-rated when transitioning operation back from the use of
curtailed operating setpoints to the use of non-curtailed operating
setpoints.
[0044] As shown in FIG. 4, the turbine controller 26 may then
command (at box 120) that the wind turbine 10 be operated at the
resulting operating setpoint(s). For example, turbine controller 26
may command that the wind turbine 10 be operated at a given
generator speed setpoint and a given generator torque setpoint. In
doing so, the turbine controller 26 may be configured to implement
any suitable control action that allows for the wind turbine 10 to
be operated at the commanded setpoints. For instance, the
controller 26 may de-rate or up-rate the wind turbine 10, as the
case may be, by commanding that one or more of the rotor blades 22
be pitched about its pitch axis 28. As indicated above, such
control of the pitch angle of each rotor blade 22 may be achieved
by transmitting suitable control commands to each pitch adjustment
mechanism 32 of the wind turbine 10. In other embodiments, the
controller 26 may implement any other suitable control action in
order to de-rate or up-rate the wind turbine 10 to the commanded
setpoints, such as by modifying the torque demand on the generator
24 (e.g., by transmitting a suitable control command to the
associated power converter (not shown) in order to modulate the
magnetic flux produced within the generator 24) or by yawing the
nacelle 16 to change the angle of the nacelle 16 relative to the
direction of the wind.
[0045] Referring now to FIG. 6, a flow diagram of one embodiment of
a method 200 for controlling the operation of a wind turbine is
illustrated in accordance with aspects of the present subject
matter. In general, the method 200 will be described herein with
reference to implementing aspects of the control algorithm 100
described above with reference to FIG. 4. However, in other
embodiments, the method 100 may be utilized in connection with any
other suitable computer-implemented algorithm. Additionally,
although FIG. 6 depicts steps performed in a particular order for
purposes of illustration and discussion, the methods discussed
herein are not limited to any particular order or arrangement. One
skilled in the art, using the disclosures provided herein, will
appreciate that various steps of the methods disclosed herein can
be omitted, rearranged, combined, and/or adapted in various ways
without deviating from the scope of the present disclosure.
[0046] As shown, at (202), the method 200 includes monitoring a
current yaw position of the nacelle. As indicated above, by
monitoring the yaw position of the nacelle 16, the turbine
controller 16 may be configured to determine which yaw sector 140
in which that nacelle 16 is currently located. Additionally, at
(204), the method 200 includes monitoring at least one
wind-dependent parameter (e.g., generator speed) and at least one
wind parameter of the wind turbine (e.g., wind speed). Moreover, at
(206), the method 200 includes determining a variance of the
wind-dependent parameter(s) over time. For example, as indicated
above, the controller 26 may be configured to calculate a standard
deviation of the generator speed occurring over a relatively short
period of time, which may be indicative of the variability of the
monitored wind parameter across such time period. Further, at
(208), the method 200 includes determining whether the calculated
variance exceeds a predetermined variance threshold and whether the
monitored wind parameter exceeds a predetermined win parameter
threshold. If so, at (210), the method 200 includes determining at
least one curtailed operating setpoint for the wind turbine based
at least in part on historical wind data for the yaw sector
associated with the current yaw position of the nacelle.
Specifically, as indicated above, the turbine controller 26 may be
configured to take into account the historical wind data for the
yaw sector 140 within which the nacelle 16 is currently located in
order to determine whether such yaw sector 140 typically
experiences rapidly changing wind conditions. If so, the controller
26 may be configured to establish a lower setpoint limit(s) for the
operating setpoint(s) in order to provide an increased operating or
safety margin for the wind turbine 10. Alternatively, if the yaw
sector 140 is not typically subjected to rapidly changing wind
conditions, the controller 26 may be configured to establish a
higher setpoint limit(s) for the operating setpoint(s), such as a
setpoint limit(s) near the normal operating setpoint(s) typically
set for the wind turbine 10. Additionally, at (212), the method 200
includes controlling the operation of the wind turbine based on the
curtailed operating setpoint(s).
[0047] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *